There’s an iconic photo of Indian Prime Minister Narendra Modi deep in conversation with Chinese President Xi Jinping right before the two world leaders — and historic opponents — sign a peace declaration. The talks, which took place in April 2018, ended with a pledge between the two countries to “maintain peace and tranquillity in all areas of the India-China border region.” It was a historic agreement after years of political and military tensions over one of the most crucial and fragile ecosystems in the world.

The China-India border, which stretches for 2,167 miles across the Himalayan region, is far from a tranquil place, though it attracts tens of thousands of mountaineers each year to brave its peaks. As humans progressively spoil the natural world, the impervious nature of the Himalayas has for centuries protected its forests, which are home to 360 unique songbird species, from mass tourism and industry.

But things are changing rapidly. An increasing number of people are moving to the Himalayan foothills, settling in towns like the bustling so-called British capital of Shimla, a tourism hub that also boasts a small airport and several colleges. Villages sitting at higher altitudes are also expanding, bringing deforestation and intensive grazing. The abundant mineral resources of the area are driving a mining boom, and melting glaciers are threatening communities living well beyond the region’s boundaries. According to the latest report by the Intergovernmental Panel for Climate Change, a global average temperature rise of more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) compared to preindustrial levels would spell disaster for high-altitude regions such as the Himalayas and Tibet, radically altering their ecosystems.

Countries are launching initiatives to prevent a massive shortage of resources for their populations, but with potentially dire consequences for international relations. China, for its part, is reportedly conducting a secretive cloud-seeding program designed to artificially increase rainfall in the Tibetan Plateau, one of the most arid regions of its territory. According to reports, China’s system consists of peppering the plain of the Tibetan Plateau with silver iodide furnaces, sometimes referred to by media as “chemical rainmakers,” that will release the silver iodine into the air and trigger the formation of new clouds as the southern monsoon winds from the Indian Ocean sweep the particles up in the sky. But solutions like these are poised to strain the fragile relationship between China and India, and the countries’ political and military tensions are also morphing the risk into a more complex threat. What’s clear is that the need for environmental diplomacy has never been greater.

“What China is doing on the Tibetan Plateau has implications not just for India, but for the whole of Asia and even beyond,” says Brahma Chellaney, a professor of strategic studies at the Center for Policy Research in Delhi. “Changing the ecology of an occupied territory which is two-thirds the size of Europe holds pretty grave implications,” he says, adding that because the Tibetan Plateau is linked with the atmospheric general circulation system of the Northern Hemisphere, it means that even Europe and North America could be affected.

Some observers of China’s cloud-seeding plan say it could dangerously change the region’s hydrology, and an investigation by the South China Morning Post, one of few available reports on the project, seems to support these concerns. However, given the government’s refusal to share any official record, public information on its impacts remains virtually nonexistent. As reported, the process is estimated to bring an additional 10 billion cubic meters of rain per year, accounting for 7 percent of China’s total water consumption.

The Wyoming Weather Modification Pilot Program, which carried out the largest study to date on cloud seeding, says the technique can be effective but is unreliable, and scientists warn it could have unpredictable consequences on the region’s monsoon patterns and, in turn, its hydrology.

While China’s Tibetan experiment, once completed, would be the biggest to date, cloud seeding has been toyed with in the past. Most recently, India tested artificial rain to ease drought in the state of Karnataka; this winter, the government made preparations to induce showers over Delhi, in a last-ditch effort to control air pollution. Although the experiment couldn’t take place due to unsuitable weather conditions, scientists think that artificial rain could provide an effective short-term solution to bad air in polluted megacities.

Since the 1940s, India and China have been competing for dominance in Asia and clashed at their shared Himalayan border. Nearly 80 years later, not much has changed. “The boundary dispute is still there. We have not reached an agreement as to where [the border] will lie. We still have different views that are still contradictory to a large extent,” says Alka Acharya, professor of Chinese studies at Jawaharlal Nehru University in Delhi. “There is a great amount of suspicion on both sides,” she tells me, “and Tibet is one of the playing fields of these tensions.”

A lack of local governance and the grip of Chinese dominance — engineered through the planned migration of tens of thousands of Han citizens to the region — makes Tibet the perfect testing ground for China’s secretive weather-modification plans. Asia is experiencing the world’s highest population growth rate and already hosts about 60 percent of the global population on just 30 percent of the planet’s land. The cloud-seeding project will add to the impacts of hundreds of new dams, planned by both India and China, that will alter the flow of major rivers and tip the region’s precarious ecological balance.

The circulation of wind in the atmosphere helps move heat and energy from the equator toward the poles. Tampering with its dynamics could alter the climate patterns of distant countries, whose governments should hold China to account, Chellaney says. “Environmental degradation is extremely serious, but it’s not always visible to the human eye, so it’s more difficult to get the international community to act,” he notes.

China is also a difficult partner when it comes to international diplomacy. Bharath Gopalaswamy, director of the South Asia Center with the Atlantic Council in Washington, D.C., says, “China has a penchant for microaggression,” and its approach to growth and development is to quietly “challenge the status quo within their own islands or anywhere else in the world” through politically controversial developments. China is not doing anything wrong, Gopalaswamy concedes, but it tends to target areas that are along sensitive borders, whether it be the Himalayas, Pakistan, or the South China Sea.

And while this strategy has fallen under scrutiny for its economic and humanitarian implications, “nobody talks about the environmental dimension of this long-standing tension [at the China-Indian border]. But that could become a force multiplier” in the future, Gopalaswamy says.

In an age of trade wars and populism, environmental diplomacy is easily forgotten, but with climate change at a tipping point and population growth spiraling, erratic weather and water scarcity are poised to become main drivers of conflicts of unprecented scale. It’s time for environmental diplomacy to be taken seriously before it’s too late.